Enable the MIRROR configuration parameter

You can set the MIRROR configuration parameter to enable
(or disable) mirroring.

Enabling mirroring starts the database server functions
required for mirroring tasks. However, when you enable mirroring,
you do not initiate the mirroring process. Mirroring does not actually
start until you create mirror chunks for a dbspace, blobspace, or
sbspace. See Using mirroring.

Enable
mirroring when you initialize the database server if you plan to create
a mirror for the root dbspace as part of initialization; otherwise,
leave mirroring disabled. If you later decide to mirror a storage
space, you can change the value of the MIRROR configuration parameter.

To
enable mirroring for the database server, you must set the MIRROR
parameter in onconfig to 1.
The default value of MIRROR is 0, indicating that
mirroring is disabled.

Do not set the MIRROR parameter to 1 if
you are not using mirroring.

To change the value of MIRROR,
you can edit the onconfig file with a text editor
while the database server is in online mode. After you change the onconfig file,
take the database server offline and then to quiescent for the change
to take effect.